1. Technical Field
The invention provides methods and systems for detecting estrus in animals, and in particular, methods and systems for determining optimal breeding time in a female animal.
2. Background
Accurate determination of estrus in cattle and other animals, including both domestic animals and wildlife, is an economically important procedure in the field of animal husbandry. An accurate estrus determination identifies the window of time in which the animal can be inseminated. In cattle, the estrous period occurs approximately every 21 days in non-pregnant females and usually lasts only about twelve to eighteen hours with peak estrus being about six hours in duration. With many animals active nocturnally, including cattle, the relatively short duration of peak estrus period can be difficult to detect without a reliable automated monitoring system. A failure to achieve pregnancy in the cycling animal can be costly, particularly in terms of production or missed opportunity.
There are several observable signs indicating that an animal is in estrus (heat). Of particular importance, females of various animal species such as domestic cows will permit themselves to be mounted by other females which may or may not be in estrus. If a mounted female allows the mount to continue for more than a few seconds, then the mounted female is likely in estrus. Although females may be mounted at times outside of estrus, females will allow themselves to be heat mounted for relatively prolonged times. When an animal is not in estrus, she will try to move out from under a mount (a false mount or false positive). Direct observation is the most common method of determining whether an animal is in heat during these episodes.
Available systems for estrus detection may require implantation of devices into the tailhead of females to sense mounting events. The use of implants presents several difficulties including the need for surgical placement, possibilities for infection from implantation, and the problem of replacing defective or damaged implanted components.
Other systems for detecting estrus provide for a visible display on the body of the female, e.g. when a mount occurs (standing or false) a colored liquid is released onto the tailhead of the mounted animal. Such systems have limited utility because estrus monitoring information is limited to visual inspection of the female. The rancher or breeder must go to a location within sight of the females in order to determine which females are in estrus. Given the short duration of estrus in most animals, this poses a significant inconvenience to the rancher and adds potential for missing the estrus even where the rancher or breeder is well intentioned. In addition, there is no indication as to whether any mount episode was associated with an animal in estrus.
Still other systems include pedometers to measure activity of the animal or vaginal probes to measure chemical changes in the vagina as the animal approaches ovulation.
However, most estrus detecting systems have a high rate of false positive estrus determinations. For example, a mounting female may maintain an extended mount even when the mounted female is not in estrus and thus is trying to move away from the mount.
Female domestic animals, particularly cows, are more physically active during estrus than at other times. This increased activity may include walking, running, and attempts to mount other animals. Increased activity amplifies the number of false positives determined by existing methods for detecting estrus.
Therefore, there is a need in the art to provide new methods and systems for detecting estrus.
Provided herein are methods and systems directed toward overcoming one or more of the problems discussed above.